Piston Spring Seat Washer 14mm

Metal plate positioned between the piston spring and the 14mm plunger in the pump drive mechanism. 3 pieces are used per pump – one for each plunger.

Application

The plate transfers the piston spring's pressing force evenly onto the plunger, providing stable, axial pressure during the cyclic reciprocating motion. It works in the drive mechanism of the AZ-L type pump with 14mm plungers.

Symptoms – when to replace

• The plate is worn or has an uneven contact surface against the spring or plunger.
• Visible dents or localized wear marks at the contact point with the spring, visible when the mechanism is disassembled.
• Uneven, pulsating pump operation despite sound valve block seals.
• Increased axial play of the plunger when the mechanism is moved by hand after removing the housing plate.

How to choose the right part

Selection is based on reference number 43041 and matching the 14mm plunger diameter – the plate is not interchangeable with versions for other plunger diameters (e.g. 12mm in AZ pumps on K 1050 TS), despite a similar appearance.

When replacing the plate, also assess the condition of the spring (43.040) and the plunger (49.021) in the same assembly – a worn plate is often accompanied by wear on these neighboring parts.

Compatibility

HD 7/122, HD 7/122 TS, HD 10/122, HD 10/122 TS, K 1152 TS, K 1152 TST – pump drive mechanism with 14mm AZ-L plungers.

[faq]

Do all 3 plates need to be replaced at once, or can they be replaced individually?|They can be replaced individually if only one shows wear. However, since all three work under identical load conditions, it's worth assessing the condition of the others while the drive mechanism is already open.

[/faq]